Small air compressors have become common tools around the home, workshop and work site. For home, recreation and other light duty uses such as inflating sports or recreation equipment or for emergency use in inflating a car tire a number of very small and lightweight compressors are available. Such tasks require relatively low-pressure compressed air and/or relatively low airflow rates. Weight is kept low and portability is maximized in these designs by use of small, low volume and/or low-pressure compressors powered by small lightweight electric motors. Additionally, significant weight, size and cost savings are achieved by the omission of a high-pressure vessel (i.e., air tank), as well as an oil lubrication system.
Many jobs, however, require higher air pressures, and/or greater instantaneous air flow demands which typically exceed the capacity of the hobby or recreational use compressors. To satisfy the demands of higher air pressure and higher airflow tasks it is necessary to increase the size of the compressor and the related motor or engine. Furthermore, rather than sizing the compressor to meet the maximum theoretical instantaneous air flow demand, it is common design practice to include a compressed air reservoir in the form of an air tank or other pressure vessel. The tank, usually with an output regulator, can hold a quantity of pressurized air to meet peak demands from serviced loads, while allowing the use of a smaller and lighter compressor that charges the tank and is capable of meeting the average compressed air flow rate for the intended use.
The air tank and the larger compressor that are typically required to meet the desired pressure and airflow levels substantially increase the weight and overall size of the compressor package. Units designed for high pressure and high volume tasks can rapidly reach a weight and size where the well-known motor vehicle mounted or towed trailer configuration is the only practical form. Still, there are a range of intermediate capacity air compressors that are common tools around the construction site and which are man portable.
Current models of man portable air compressor packages comprise a stand or supporting structure on or in which are mounted a motor or engine, an air compressor, an air tank, a discharge manifold and various valves, instrumentation and controls. Many of the larger portable configurations are provided with wheels, in what is often referred to as a wheelbarrow configuration, so that they can be moved by a single user. Examples of wheeled air compressors include Models D55170 and D55270, which are marketed by DeWalt.
Still, some users of intermediate capacity professional grade compressors find it necessary or desirable to have a compressor that is capable of being lifted and carried by hand. One common approach taken by air compressor manufacturers to improve the portability of such intermediate capacity professional grade compressors has been to redesign the air compressor so as to reduce its weight. Despite such efforts, intermediate capacity professional grade compressors frequently weigh more than 50 pounds and thus remain difficult to lift and move by hand, even for those users who are physically strong.
Aside from the issue of their weight, hand-portable intermediate capacity professional grade compressors are also known to be quite cumbersome to transport. In this regard, the configurations that use two cylindrical tanks or a single pancake tank (i.e., a cylindrical tank of large diameter but small height with convex ends) have become common, as have the mounting schemes for mounting the compressor and the motor. For example, configurations that use two cylindrical tanks typically mount the compressor and motor alongside the tanks, whereas configurations that use a single pancake tank typically mount the compressor and motor on an end of the tank.
These conventional air compressor arrangements provide a package with a relatively large base or footprint, and a center of gravity that is positioned in an approximately centered position within the footprint. While such arrangements provide the air compressor with a configuration that is relatively stable during its operation, lifting and carrying air compressors with these configurations tends to be rather awkward and difficult. In this regard, these configurations typically employ a handle (for lifting and carrying the air compressor) that is attached to an appropriate structure, such as the stand or the air tank, at a location that is located vertically above the center of gravity of the entire air compressor package. The handle is generally oriented in a manner that requires the air compressor package to be lifted vertically upwards and carried in an orientation that is substantially the same as the orientation in which it is operated.
Lifting and carrying the known intermediate air compressor packages in this manner, however, is relatively difficult, since the footprint of these air compressor packages tends to be relatively large and thus requires the user to hold the air compressor package with a somewhat outstretched arm such that the wrist of the user is in a state of flexion. In an effort to bring the air compressor package's center of gravity closer to the central axis of the user, the user will typically tilt their upper body away from the load of the air compressor package and thus will lift and transport the air compressor package with a body posture that is uncomfortable and awkward.